Northwest Africa 15583 (NWA 15583)
Classification: Lunar meteorite (feldspathic breccia)
History: Purchased by Mark Lyon in 2022 from an Algerian dealer.
Petrography: (A. Irving, UWS and P. Carpenter, WUSL) Breccia composed of relatively large (up to 2 cm) and relatively closely-packed angular lithic clasts plus some related mineral clasts in a sparse fine grained, partly vesicular and partly glassy matrix. The lithic clasts are mostly anorthite-rich with varying amounts of olivine, low-Ca pyroxene, pigeonite, subcalcic augite and augite. Accessory phases include low-Ti chromite, ilmenite, troilite, kamacite and Zr-bearing rutile.
Geochemistry: Olivine (Fa22.5-43.7, FeO/MnO = 83-96, N = 8), low-Ca pyroxene (Fs20.9-37.9Wo2.5-3.8, FeO/MnO = 49-59, N = 3), pigeonite (Fs26.2Wo6.6, FeO/MnO = 54), subcalcic augite (Fs14.7Wo29.9, FeO/MnO = 49), augite (Fs10.4-11.4Wo41.8-41.6; Fs8.4Wo48.1; FeO/MnO = 38-40, N = 3), anorthite (An96.1-98.2Or0.0, N = 4).
Classification: Lunar (feldspathic breccia).